Oxide films (SiOx films) prepared by the chemical vapor deposition method (CVD method) and so on are currently used as interlayer insulation films for semiconductor devices. Due to a high dielectric constant thereof, however, inorganic insulation films such as oxide films can hardly achieve speeding up and upgrading of semiconductor devices. Accordingly, organic materials are being studied for use as interlayer insulation films having a low dielectric constant. Such organic materials are required to have excellent heat resistance, excellent electrical properties and also a low dielectric constant.
As such organic materials, polyimide resins, polyquinoline resins, polyquinoxaline resins and so on have been studied. (For example, see Patent Document 1).
In general, however, resin films composed of polyimide resins have problems such as low heat resistance, high dielectric constant and high moisture absorptivity. Consequently, due to reliability thereof, use of polyimide resins is limited to some semiconductor elements such as a bipolar semiconductor element.
On the other hand, polyquinoline resins and polyquinoxaline resins have higher heat resistance, a lower dielectric constant and a lower moisture absorptivity than those of polyimide resins. However, since polyquinoline resins and polyquinoxaline resins are thermoplastic resins, they have a problem that they may change shapes thereof by exposure to temperatures higher than glass-transition points thereof, and thus circuit patterns of semiconductor elements cannot be retained during semiconductor production.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-195853